The present invention relates to a variable displacement swash plate compressor.
Japanese Laid-Out Patent Publication No. 5-172052 describes a conventional variable displacement swash plate compressor (hereafter simply referred to as the compressor). The compressor has a housing including a front housing member, a cylinder block, and a rear housing member. The front housing member and the rear housing member each includes a suction chamber and a discharge chamber. The cylinder block includes a swash plate chamber and cylinder bores. A rotatable drive shaft is supported in the housing. A swash plate that is rotatable together with the drive shaft is arranged in the swash plate chamber. A link mechanism is located between the drive shaft and the swash plate to allow the inclination angle of the swash plate to change. The inclination angle refers to an angle of the swash plate relative to a plane orthogonal to the rotation axis of the drive shaft. Each cylinder bore accommodates a reciprocal piston. Two shoes are provided for each piston to serve as a conversion mechanism that uses the rotation of the swash plate to reciprocate the piston in the corresponding cylinder bore with a stroke that is in accordance with the inclination angle of the swash plate. An actuator, which includes a movable body and a control pressure chamber, changes the inclination angle of the swash plate. A control mechanism regulates the pressure of the control pressure chamber to control the actuator.
The link mechanism includes a lug arm, first and second arms, and a movable body. The lug arm is fixed to the drive shaft and located in front of the swash plate chamber. The first arm is located on the front surface of the swash plate, and the second arm is located on the rear surface of the swash plate. The first arm pivotally couples the lug arm and the swash plate. The second arm pivotally couples the movable body and the swash plate.
In the compressor, the control mechanism increases the pressure of the control pressure chamber with the pressure of the refrigerant in the discharge chamber to move the movable body toward the swash plate along the axis of the drive shaft. As a result, the movable body pushes the swash plate and increases the inclination angle of the swash plate. The swash plate comes into contact with the lug arm when the inclination angle of the swash plate becomes maximal. This allows the compressor displacement to be maximized for each rotation of the drive shaft.
In the conventional compressor described above, contact of the swash plate and the lug arm restricts the swash plate at the maximum inclination angle. The lug arm is fixed to the drive shaft. Thus, contact of the swash plate and the lug arm may produce an impact that generates vibration and lowers the durability of the compressor. Further, contact of the swash plate and the lug arm produces noise. Such situations become further noticeable when quickly increasing the compressor displacement to the maximum amount.